CN110512120B

CN110512120B - Method for manufacturing crystalline aluminum-iron-silicon alloy

Info

Publication number: CN110512120B
Application number: CN201910378306.3A
Authority: CN
Inventors: Z·刘; 齐腾蛟; J·R·萨尔瓦多; R·S·库克雷亚
Original assignee: GM Global Technology Operations LLC
Current assignee: GM Global Technology Operations LLC
Priority date: 2018-05-21
Filing date: 2019-05-08
Publication date: 2022-02-22
Anticipated expiration: 2039-05-08
Also published as: CN110512120A; DE102019111382A1; US10913992B2; US20190352748A1; DE102019111382B4

Abstract

The present invention provides a method of making a crystalline aluminum-iron-silicon alloy and optionally automotive parts comprising the alloy, comprising forming a substantially homogeneous melt by melting aluminum, iron and silicon raw materials in an inert environment, subsequently solidifying the melt to form a composite ingot comprising a plurality of crystalline phases, and annealing the ingot under vacuum by heating at a temperature of 850 ℃ to 1000 ℃ to obtain an annealed ingot, wherein the predominant crystalline phase is FCC Al₃Fe₂And (3) Si. The feedstock may further include one or more additives such as zinc, zirconium, tin, and chromium. Melting may occur in FCC Al₃Fe₂Above the melting point of the Si crystalline phase, or at a temperature of about 1100 ℃ to about 1400 ℃. The annealing may occur under vacuum conditions.

Description

Method for manufacturing crystalline aluminum-iron-silicon alloy

Introduction to the design reside in

Iron aluminum compounds (e.g., FeAl and Fe)₃Al) is an intermetallic compound with a defined stoichiometry and ordered crystal structure. Many iron aluminum compounds exhibit excellent high temperature oxidation resistance, relatively low density, high melting point, high strength to weight ratio, good wear resistance, easy workability, and low production cost, as they typically do not include rare elements, which makes them attractive alternatives to stainless steel in industrial applications. However, at low to moderate temperatures, iron aluminum compounds often have poor ductility and low fracture toughness. At elevated temperatures, iron aluminum compounds have been found to exhibit limited creep resistance and high thermal conductivity. Increasing the aluminum content of these materials can reduce their density and enhance the formation of a protective oxide layer at high temperatures, but can also significantly reduce their ductility in aqueous environments (e.g., air) due to a phenomenon known as hydrogen embrittlement.

Ternary Al-Fe-Si intermetallics are of interest for alloy development due to their potentially advantageous properties. In particular, the addition of silicon in the Al-Fe binary system may result in a ternary Al-Fe-Si intermetallic compound having a crystalline structure that exhibits a combination of relatively low density and good mechanical properties, such as good stiffness and ductility. Accordingly, there is a need in the art for a method of making crystalline Al-Fe-Si alloys having a defined stoichiometry and ordered crystal structure that exhibits a desirable combination of relatively low density and good chemical, thermal and mechanical properties.

Disclosure of Invention

A method of making a crystalline aluminum-iron-silicon alloy is provided and includes forming a composite ingot comprising a plurality of crystalline phases by melting aluminum, iron and silicon starting materials in an inert environment to form a substantially homogeneous melt and subsequently solidifying the melt, and annealing the ingot under vacuum by heating at a temperature of 850 ℃ to 1000 ℃ to obtain an annealed ingot. The main crystalline phase of the annealed ingot is FCC Al₃Fe₂And (3) Si. Melting may include heating to a temperature of about 1100 ℃ to about 1400 ℃. The melting may include heating toHigher than FCC Al₃Fe₂The melting point of the Si crystal phase. The substantially inert environment may include an argon atmosphere. Solidifying the melt may include cooling the melt to at least about 1050 ℃ in an inert environment. The annealing may occur under vacuum at a pressure of less than about 60 millitorr. The composite ingot may comprise less than about 0.01% FCC Al₃Fe₂A Si crystal phase. The annealed ingot may include less than about 1% of a triclinic Al-Fe-Si crystalline phase and less than about 5% of a hexagonal Al-Fe-Si crystalline phase. At least about 90% of the annealed ingot may comprise crystalline FCC Al₃Fe₂A Si phase. The annealed ingot may include less than about 1% amorphous phase material. The method may further include grinding the composite ingot prior to annealing. The melt may include about 31% to about 35% aluminum, about 50% to about 55% iron, and about 11% to about 13% silicon.

A method of making a crystalline ferroaluminum silicon alloy is provided. The method includes forming a composite ingot comprising a plurality of crystalline phases by melting aluminum, iron and silicon raw materials at a temperature of at least about 1050 ℃ and subsequently solidifying the melt, and finally annealing the ingot by heating at a temperature elevated to about 1000 ℃ to obtain an annealed ingot. At least about 90% of the annealed ingot comprises FCC Al₃Fe₂A Si crystal phase. The melting may occur in an inert environment. The melt may include about 31% to about 35% aluminum, about 50% to about 55% iron, and about 11% to about 13% silicon. The annealing may occur under vacuum at a pressure of less than about 60 millitorr. The composite ingot may comprise less than about 0.01% FCC Al₃Fe₂A Si crystal phase.

A method of manufacturing an automotive component is provided. The method includes forming a composite ingot comprising a plurality of crystalline phases by melting aluminum, iron and silicon raw materials in an inert environment at a temperature of about 1100 ℃ to about 1400 ℃ and then solidifying the melt, and finally annealing the ingot by heating at a temperature of 850 ℃ to 1000 ℃, under a vacuum pressure of less than about 60 mtorr, and then cooling to obtain an annealed ingot. At least about 90% of the annealed ingot comprises FCC Al₃Fe₂A Si crystal phase. The composite ingot may comprise less than about 0.01% FCC Al₃Fe₂A Si crystal phase. The melt may include about 31% to about 35% aluminum, about 50% to about 55% iron, and about 11% to about 55% ironAbout 13% silicon.

Other objects, advantages and novel features of the exemplary embodiments will become apparent from the following detailed description of the exemplary embodiments and the accompanying drawings.

Drawings

Fig. 1 illustrates an X-ray diffraction pattern of a molten composite ingot according to one or more embodiments; and

fig. 2 shows an X-ray diffraction pattern of an annealed ingot in accordance with one or more embodiments.

Detailed Description

Aluminum, iron and silicon are relatively abundant materials. Theoretically, iron aluminum compounds (e.g., quasi-equilibrium cubic Al)_xFe_ySi_zTernary phase) at a density close to that of titanium (e.g., less than 5 g/cm)³) Has extreme properties but is an order of magnitude less costly than titanium. For example, cubic Al_xFe_ySi_zThe phases have excellent stiffness, high temperature strength, ductility (e.g., at least 5 slip systems in the crystal structure, 12 slip systems in the Face Centered Cubic (FCC) structure, and up to 48 slip systems in the Body Centered Cubic (BCC) system) and tensile strength at room temperature (e.g., greater than or equal to 450 MPa). These phases also have a high oxidation resistance due to the presence of a large amount of aluminium.

It is difficult to manufacture a catalyst having a predominant FCC Al without the use of expensive powder materials, mechanical alloying, and/or other energy intensive processes₃Fe₂Al-Fe-Si alloy with Si crystal phase. The melting and annealing processes disclosed herein can be used to produce a material having a composition comprising predominantly FCC Al₃Fe₂A crystalline aluminum iron silicon alloy of the intended microstructure of the Si crystalline phase. In addition, the presently disclosed melting and annealing heat treatment methods may be used in conjunction with one or more powder metallurgy processes to produce shaped crystalline aluminum iron silicon alloy parts.

As used herein, the term "aluminum-iron-silicon alloy" or "Al-Fe-Si alloy" refers to a material that includes aluminum (Al), iron (Fe), and silicon (Si). The Al-Fe-Si alloy may further include one or more additives including zinc (Zn), chromium (Cr), zirconium (Zr), boron (B), and the like. Specific details of interest hereinThe expected product of the Al-Fe-Si alloy and all disclosed methods is an intermetallic FCC Al₃Fe₂Si crystal phase, characterized by a lattice parameter a, b, c, 1.0806nm, cell parameter

10.806(2), Fd-3m space group, NiTi₂Structural and cF96Pearson notation. Although designated as Al for simplicity₃Fe₂Si, but understood to be FCC Al₃Fe₂The Si phase may show a slight deviation in composition. For example, for FCC phase Al_xFe_ySi_zX may equal about 2.99 to about 3 and y may equal about 1.99 to about 2.25, such that z is normalized to equal 1. In other words, FCC phase Al₃Fe₂The Si may comprise from about 48 atomic percent ("at.%) to about 50 at.% Al, from about 33.3 at.% to about 36 at.% Fe, and from about 16 at.% to about 16.7 at.% Si. Percentages ("%") refer to weight percentages unless otherwise indicated.

Provided herein are melting and annealing processes that produce FCC Al₃Fe₂An Al-Fe-Si alloy of Si crystal phases as the main phase and the smallest amorphous phase, if any, or an unexpected crystal phase, such as a hexagonal phase or a triclinic phase. FCC Al as the predominant phase in crystalline Al-Fe-Si alloys₃Fe₂The formation of the Si crystalline phase, and its storage at room temperature, may impart certain desirable properties to the crystalline Al-Fe-Si alloy. For example, alloyed with Al-Fe-Si or other crystalline phases (i.e., non-FCC Al)₃Fe₂Si crystalline phase) may be relatively light, may exhibit excellent mechanical strength at high temperatures, high oxidation resistance, and relatively high stiffness and ductility compared to partially amorphous Al-Fe-Si alloys. As used herein, with respect to a particular phase in an Al-Fe-Si alloy, the term "predominant" and its various word forms and conjugates means that such phase is the single largest phase by weight in the Al-Fe-Si alloy, with the weight fraction of the predominant phase in the Al-Fe-Si alloy being greater than the weight fraction of all other phases in the Al-Fe-Si alloy, used alone or in combination.

The method includes first melting aluminum, iron and silicon raw materials, and optionally one or more additive materials as described below. The one or more starting materials may be in the form of pellets, tablets, or powders, and the like. Advantageously, the starting material may be provided in non-powder form, thereby avoiding the cost of a powder starting material. The aluminum feedstock purity can be as low as 95%, but 99% pure aluminum feedstock is generally available and suitable. For example, the aluminum feedstock can include aluminum pellets having a purity of about 99% to about 99.99% and a diameter of about 5mm to about 20 mm. Iron feedstock purity can be as low as 95%, but 97% pure iron feedstock is generally available and suitable. For example, the iron feedstock may include pieces having a purity of about 99% to about 99.99% (e.g., a length and width of about 5mm to about 40mm, and a thickness of about 1mm to about 10 mm). Silicon feedstock purity can be as low as 95%, but aluminum feedstock of 99.9% purity is generally available and suitable. For example, the silicon feedstock may include silicon pellets or chips having a purity of about 99.9% and have various sizes.

The respective amounts of Al, Fe, and Si in the Al-Fe-Si alloy are selected to provide the alloy with the ability to form the desired crystal structure during fabrication. In particular, the respective amounts of Al, Fe and Si in the Al-Fe-Si alloy are selected to provide the alloy with a composition comprising predominantly FCC phase Al₃Fe₂Crystal structure of Si. It has been found that in practice FCC Al in crystalline Al-Fe-Si alloys₃Fe₂The respective amounts of aluminum, iron and silicon in the Si crystal phase may be slightly different from the amounts predicted by the above empirical formula. For example, the feedstock in the melt may comprise about 31% to about 35% aluminum, about 50% to about 55% iron, and about 11% to about 13% silicon.

As described below, the Al-Fe-Si alloy may optionally further include one or more additives, such as zinc, chromium, zirconium, and/or boron, among others. These additives may be present in an amount of about 3% to about 10% of the alloy. Nonetheless, the additional elements not intentionally introduced into the Al-Fe-Si alloy composition may be inherently present in the alloy in relatively small amounts, e.g., less than 4.5%, preferably less than 2.0%, and more preferably less than 0.02% by weight of the Al-Fe-Si alloy. For example, these elements may be present as impurities in the raw materials used to prepare the Al-Fe-Si alloy composition.

In some embodiments, the composition of the feedstock may include about 34% to about 35% aluminum, about 53% to about 54% iron, and about 11.5% to about 12.5% silicon. In one such embodiment, the composition of the feedstock may include about 34.5% aluminum, about 53.5% iron, and about 12% silicon.

In some embodiments, the composition of the feedstock may include about 32.5% to about 33.5% aluminum, about 52.25% to about 53.25% iron, about 11.25% to about 12.25% silicon, and about 2% to about 3% zinc. In one such embodiment, the composition of the feedstock may include about 33% aluminum, about 52.7% iron, about 11.8% silicon, and about 2.5% zinc. For example, such alloys may exhibit increased crystalline twinning and improved ductility due to the inclusion of zirconium.

In some embodiments, the composition of the feedstock may include about 33% to about 34% aluminum, about 51% to about 52% iron, about 11% to about 12% silicon, about 2.25% to about 3.25% chromium, about 0.1% to about 0.4% zirconium, and up to about 0.1% boron. In one such embodiment, the composition of the feedstock may include about 33.4% aluminum, about 51.9% iron, about 11.6% silicon, about 2.8% chromium, about 0.2% zinc, and about 0.07% boron. For example, such alloys may exhibit enhanced grain boundary refinement and improved ductility.

In some embodiments, the composition of the feedstock may include about 31.5% to about 32.5% aluminum, about 50.5% to about 51.5% iron, about 11% to about 12% silicon, about 2% to about 3% zinc, about 1.55% to about 3.25% chromium, about 0.1% to about 0.4% zirconium, and up to about 0.1% boron. In one such embodiment, the composition of the feedstock may include about 32% aluminum, about 51.1% iron, about 11.4% silicon, about 2.4% zinc, about 2.7% chromium, about 0.2% zinc, and about 0.07% boron. For example, such alloys may exhibit increased crystalline twinning, enhanced grain boundary refinement, and improved ductility.

In some embodiments, the composition of the feedstock may include about 32% to about 33% aluminum, about 51.75% to about 52.75% iron, about 11% to about 12% silicon, and about 3% to about 4% zirconium. In one such embodiment, the composition of the feedstock may include about 32.6% aluminum, about 52.3% iron, about 11.7% silicon, and about 3.4% zirconium. For example, such alloys may exhibit increased grain refinement due to the inclusion of zirconium.

In some embodiments, the composition of the feedstock may include about 32% to about 33% aluminum, about 51.25% to about 53.25% iron, about 11% to about 12% silicon, and about 4% to about 5% tin. In one such embodiment, the composition of the feedstock may include about 32.3% aluminum, about 51.7% iron, about 11.6% silicon, and about 4.4% tin. For example, such alloys may exhibit increased crystalline twinning due to the inclusion of tin.

At least above FCC Al₃Fe₂The melting point of the Si phase (-1050 c) melts the raw materials to form a generally homogeneous melt. The melting temperature remains below the melting point of iron (-1538 ℃) and silicon (-1414 ℃) and optionally below any additives, except zinc and tin. Thus, in some embodiments, the feedstock is melted at a temperature of about 1050 ℃, a temperature of about 1100 ℃ to about 1400 ℃. Increasing the additives in the Al-Fe-Si alloy may require higher melting temperatures. For example, the feedstock may be melted in a boron nitride crucible. Alternatively, the raw material may be melted in a mold, such as an automotive part mold. In such embodiments utilizing an automotive part mold or the like, the composite ingot comprises an automotive part. The raw materials may be melted in an inert environment, thereby precluding undesirable oxidation or phase formation. For example, the inert environment may comprise an argon and/or neon atmosphere.

The melt is then solidified to form a composite ingot. After melting is complete, the melt may be cooled in an inert environment until the melt solidifies or substantially solidifies (typically around FCC Al)₃Fe₂Near the melting point of the Si phase) to minimize the macrocavity. In some embodiments, the melt is slowly cooled in an inert environment until a temperature of about 1100 ℃ down to about 1000 ℃ is reached. The composite ingot may be further cooled to ambient temperature under ambient atmospheric conditions. Prior to annealing, the composite ingot may optionally be ground to a particle size that exhibits characteristics (e.g., tap density and flowability) suitable for use in powder metallurgy processes. The grinding may be performed using a roll mill, a ball mill or other suitable method. For example, canTo grind the composite ingot to a particle size of about 50 μm to about 500 μm.

The composite ingot may comprise one or more crystalline phases, and optionally one or more amorphous phases. For example, the composite ingot may comprise Fe_1.7Al₄Hexagonal (P63/mmc) Si phase, Fe₃Al_0.25Si_0.75Cube (Fm-3m)

Crystalline phase and Fe₃Al cubic (Pm-3m) crystal phase. Thus, one or more non-Al-Fe-Si crystalline phases (e.g., Fe) may be present₃Al cubic (Pm-3m) crystal phase). In some embodiments, the composite ingot may comprise less than about 0.01% FCC Al₃Fe₂Si crystal phase, or substantially free of FCC Al₃Fe₂A Si crystal phase.

Subsequently under less than FCC Al₃Fe₂Annealing the composite ingot at a temperature at the melting point of the Si crystalline phase to obtain an annealed ingot. Annealing to obtain an annealed ingot, wherein FCC Al₃Fe₂The Si crystal phase is the predominant crystal phase. In addition, the annealed ingot contains very little or substantially no amorphous or low symmetry crystalline phases, such as triclinic Al-Fe-Si (e.g., Al)₃Fe₂Si) crystalline phase. In some embodiments, at least about 80%, at least about 85%, or at least about 90% of the annealed boules comprise crystalline FCC Al₃Fe₂A Si phase. Additionally or alternatively, in some embodiments, the annealed boule comprises less than about 1% amorphous phase material. Additionally or alternatively, in some embodiments, the annealed ingot comprises less than about 1% of triclinic Al-Fe-Si crystalline phases. Additionally or alternatively, in some embodiments, the annealed ingot comprises less than about 5% hexagonal Al-Fe-Si (e.g., Al)₃Fe₂Si) crystalline phase.

The annealing occurs at a temperature of at least about 800 ℃, at least about 825 ℃, or at least about 850 ℃. In some embodiments, the annealing occurs at a temperature of about 850 ℃ to about 950 ℃, or about 850 ℃ to about 1000 ℃. Increasing the annealing temperature may reduce the annealing time, which may be optimized for a particular alloy composition. The composite ingot may be annealed for a period of time that suitably forms a desired amount of FCC Al₃Fe₂A Si crystal phase. In some embodiments, the composite ingot may be annealedFrom about 2 hours to about 24 hours.

The annealing may be performed in a vacuum environment and/or an inert environment. In some embodiments, the annealing occurs under high vacuum. "high vacuum" conditions may include about 60 mTorr to about 0.001 mTorr, or more preferably about 6 mTorr to about 0.001 mTorr. A vacuum environment may achieve the same purpose as an inert environment (e.g., an argon environment), but is less suitable for alloys containing relatively volatile additives (e.g., zinc). In some embodiments, the annealing occurs in an argon atmosphere. In some embodiments, the annealing occurs in a vacuum and an argon atmosphere. In some embodiments, annealing occurs at N₂An atmosphere, for example, where a nitride layer is formed on the composite ingot is contemplated. After annealing, the annealed ingot may be cooled.

Stable FCC Al₃Fe₂The quality of Si crystalline phase alloys makes them suitable for use in parts of automobiles or other vehicles (e.g., motorcycles, boats). For example, stable FCC Al₃Fe₂Si-phase alloys may be suitable for forming lighter engine valves or other lightweight valves, for forming lightweight pistons, for forming rotating and reciprocating components of internal combustion engines, and/or for use in turbocharger applications (e.g., forming turbocharger wheels). Stable FCC Al₃Fe₂The Si crystalline phase alloys may also be used in various other industries and applications, including aerospace components, industrial equipment and machinery, farm equipment, and/or heavy machinery, as non-limiting examples. In some embodiments, the components may be formed into a desired shape during the melting step. Alternatively, the annealed ingot may then be formed into a component (e.g., an automotive component) using any suitable technique, such as rolling, forging, stamping, powder metallurgy or casting (e.g., die casting, sand casting, permanent die casting, etc.), and the like.

Examples of the present invention

Aluminum, iron and silicon raw materials were combined to form a 400g melt containing 35% aluminum, 53% iron and 12% silicon. The raw materials were melted at 1200 ℃ for 5 minutes to form a cylindrical composite ingot having a diameter of about 3.8cm and a height of 7.7 cm. The resulting composite ingot was X-rayed using a D8-Advance Davinci diffractometer in a Bragg Brentano configuration using copper Kalpha radiationLine diffraction (XRD). Data was collected from 10-90 2 theta using a 0.02 deg. step size and an integration time of 1 second/step. Rietveld refinement was performed using diffrac. sutite TOPAS software. Fig. 1 shows the XRD pattern of the prepared composite ingot. The XRD pattern of the prepared composite ingot showed about Fe_1.7Al₄Hexagonal (P63/mmc) Si phase (represented by the triangles in FIG. 1), about 23% Fe₃A_l0.25Si_0.75Cubic (Fm-3m) crystalline phase (represented by the circles in FIG. 1), about 5% Fe₃The composition of the Al cubic (Pm-3m) crystalline phase (represented by the star in FIG. 1) and the unidentifiable phase (represented by the square in FIG. 1).

The composite ingot was then annealed at 950 ℃ for 24 hours under a vacuum of 0.01 millitorr to form an annealed ingot. The resulting ingot was XRD performed using a D8-Advance Davinci diffractometer in a Bragg Brentano configuration using copper ka radiation. Data was collected from 10-90 2 theta using a 0.02 deg. step size and an integration time of 1 second/step. Rietveld refinement was performed using diffrac. sutite TOPAS software. Fig. 2 shows XRD patterns of the prepared annealed ingots. The XRD pattern of the as-prepared ingot showed about 92% Fe₂Al₃Si FCC (Fd-3m) crystalline phase (represented by triangles in FIG. 2), about 5% Fe₃Al_0.25Si_0.75An FCC (Fm-3m) crystalline phase (represented by a circle in FIG. 2) and about 3% Fe₂₃Al₈1Si₁₅Hexagonal (P63/mmc) crystalline phase (indicated by an asterisk in FIG. 2). These results show that large amounts of FCC Fe can be used without using powdered feedstock or mechanical alloying₂Al₃The Si crystalline phase forms an ingot or automotive part. Similar results were obtained with only about 8 hours of annealing under similar conditions.

While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the disclosure. As previously mentioned, the features of the various embodiments may be combined to form further embodiments of the invention that may not be explicitly described or illustrated. While various embodiments may be described as providing advantages or being preferred over other embodiments or prior art implementations in terms of one or more desired characteristics, those of ordinary skill in the art will recognize that one or more characteristics or features may be compromised to achieve desired overall system attributes, which depend on the particular application and implementation. These attributes may include, but are not limited to, cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, maintainability, weight, manufacturability, ease of assembly, and the like. Accordingly, described embodiments that are less desirable than other embodiments or prior art implementations in one or more features are outside the scope of the present disclosure and may be desirable for particular applications.

Claims

1. A method of making a crystalline ferroaluminum silicon alloy, the method comprising:

forming a composite ingot comprising a plurality of crystalline phases by melting aluminum, iron, and silicon raw materials in an inert environment to form a substantially homogeneous melt and subsequently solidifying the melt, wherein the melt comprises 31 to 35 weight percent aluminum, 50 to 55 weight percent iron, and 11 to 13 weight percent silicon; and

annealing the ingot under vacuum by heating at a temperature in the range of 850 ℃ to 1000 ℃ to obtain an annealed ingot, wherein the annealed ingot comprises at least 90 wt.% FCC Al₃Fe₂Si，

Wherein melting comprises heating above the FCC Al₃Fe₂The melting point of the Si crystal phase.

2. A method of making a crystalline ferroaluminum silicon alloy, the method comprising:

forming a composite ingot comprising a plurality of crystalline phases by melting aluminum, iron, and silicon raw materials at a temperature of at least 1050 ℃ and subsequently solidifying the melt, wherein the melt comprises 31 to 35 wt.% aluminum, 50 to 55 wt.% iron, and 11 to 13 wt.% silicon; and

annealing the ingot by heating at a temperature of up to 1000 ℃ to obtain an annealed ingot, wherein the annealed ingot comprises at least 90 wt.% ofFCC Al₃Fe₂A Si crystal phase.

3. A method of manufacturing an automotive component, the method comprising:

forming a composite ingot comprising a plurality of crystalline phases by melting aluminum, iron, and silicon raw materials in an inert environment at a temperature of 1100 ℃ to 1400 ℃ and subsequently solidifying the melt, wherein the melt comprises 31 wt.% to 35 wt.% aluminum, 50 wt.% to 55 wt.% iron, and 11 wt.% to 13 wt.% silicon; and

annealing the ingot under vacuum at a pressure of less than 60 mTorr by heating at a temperature in the range of 850 ℃ to 1000 ℃ and subsequently cooling to obtain an annealed ingot, wherein the annealed ingot comprises at least 90 wt.% FCC Al₃Fe₂A Si crystal phase.

4. The method of claim 1, wherein melting comprises heating to a temperature of 1100 ℃ to 1400 ℃.

5. The method of any of the above claims 1-3, wherein annealing occurs under vacuum at a pressure of less than 60 mTorr.

6. The method of any of the preceding claims 1-3, wherein the composite ingot comprises less than 0.01 wt% FCC Al₃Fe₂A Si crystal phase.

7. The method of any of the preceding claims 1-3 wherein the annealed ingot comprises less than 1 wt.% of a triclinic Al-Fe-Si crystalline phase and less than 5 wt.% of a hexagonal Al-Fe-Si crystalline phase.

8. The method of any one of claims 1 to 3 wherein the annealed ingot comprises less than 1 wt% amorphous phase material.